Work starts on project to build solar bridge at Blackfriars

Work has begun on what may be the world’s largest solar bridge as part of the new Blackfriars railway station in London.

UK firm Solarcentury plans to install more than 6,000m2 of photovoltaic (PV) panels over the Victorian bridge across the Thames, providing an estimated 900,000kWh of electricity every year.

Network Rail estimates that this will cover around 50 per cent of the station’s energy usage and reduce CO2 emissions by around 511 tonnes per year. It will cost around £7.3m, paid for by the Department for Transport’s safety and environment fund.

Other energy-saving measures at the new station will include rain-harvesting systems and sun pipes for natural lighting.

London-based Solarcentury worked with engineering company Jacobs to incorporate solar PV into the station’s 343m long and 37m wide roof. The solar modules used are manufactured by Sanyo Electric.

Solarcentury’s design engineer for the project, Simona Mameli, told The Engineer that she had to use smaller solar inverters with integrated components in order to fit as many PV modules as possible into the unusual roof design.

‘We are extremely tight in space on the roof so we are trying to maximise the number of modules we want to put on it. They will just barely fit,’ she said.

Once PV modules have been installed on the first four roof panels, the operation will pause to reassess the design, recommencing by the end of December with the aim of installing modules on all 98 roof panels by spring 2012.

‘We have rows of modules on the roof that are nearly 15m long and we have spare space of 190mm so it is extremely tight,’ said Mameli. ‘That’s why we might need, according to the position of the roof seams, to position the clamps a bit differently.’

Shigeki Komatsu, solar division director of Sanyo Component Europe, said: ‘The high efficiency of our solar modules makes them ideal for structures where maximum power generation is required from an area where load must be considered.

‘With our solar modules on this well-known London landmark, Sanyo hopes to raise awareness and understanding of solar and other renewable energy technologies, demonstrating how they can both help the city environment and minimise the onset of climate change.’

The bridge, built in 1886, will form the foundation of the new Blackfriars station as part of Network Rail’s Thameslink upgrade. The programme should enable longer trains to run on the line between Bedford to Brighton and is due to finish in 2018.

Lindsay Vamplew, Network Rail’s project director for Blackfriars, said: ‘We’re creating a spacious, modern station and delivering a vastly improved train service for passengers, while at the same time installing London’s largest solar array to make Blackfriars more environmentally friendly and sustainable.

‘The Victorian rail bridge at Blackfriars is part of our railway history. Constructed in the age of steam, we’re bringing it bang up to date with 21st century solar technology to create an iconic station for the city.’

The world’s first solar bridge, the 470m Kurilpa footbridge in Brisbane, Australia was constructed in 2009. It provides around 40,000kWh of electricity every year.

As far as I can see, Brian has got it right. He clearly stated that he was talking about average watts ie. the average power delivered over 24 hours and over various weather conditions and this would appear to be the appropriate measure to use.

@ Brian Pollard, wind power was also a lot more expensive 20/30 years ago when the largest turbines were 20kW rather than the modern 5MW turbines. So upscaling turbine size and economies of scale are continuing to bring down the levelised cost of wind energy ($/kWh). The same is true of solar PV, we are continuing to see significant price reductions are production is upscaled and cheaper production methods are developed, this trend is expected to continue for some time. By contrast the cost of fossil fuel and nuclear energy continue to rise due to scaricty and safety requirements respectively.

1.1MW is probably the peak output, midday sun, middle of summer. Taking into account average cloudiness, night time, seasons, and reduction in PV cell efficiency over time, will reduce that 1.1MW down to a lot less - e.g. 102.7kW.

At 900,000 kWh every year, then over 20 years, it'll have generated 900000*20 = 18,000,000 kWh.

The problem is the Engineer article - the array is supposed to produce 900 MWh per year not kWh. A 1.1 MW array costing £6.6 per watt operating for the equivalent of 2.2 hours full power a day. And it will be at its best when wind is not - low cloud windless days.

I think you'll find that Mr Pollard's sums are correct. An average of 900000kWh/yr does indeed translate to approximately 103kW every day. That means he was correct to point out the £71 per installed average Watt.

A nice project , I agree, but startlingly expensive. It should fall into the category of an architectural experiment, such as the Gherkin. As such, in my view, it should not be paid for by the public purse.

I just don't get this. If, as mentioned, the commercial rate is 10p/kWh, then the annual value of electricity produced is £90,000. If we double that to allow for FiTs subsidies, it's still only £180k per annum. Divide that into £7.3m and the payback is 40.5 years! Is it me?

James R finally got the prospective right. the cost (assuming 20 year life span) is 0.41 pounds/kWh (not exactly perfect because there is some performance degrade over time. Since the power value starts at 3.5 time the present rate 0.12 pounds/kWhr the cost of power would have to increase at 11.5% to equal the stabilized power produced by the solar panels.

By the way, the solar panels should last at least 40 years even though the inverters will have to be replaced once or twice.